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砷作为饮用水中三致作用的污染物,导致越来越严重的环境问题。人造菱铁矿对水中的砷去除效率高。为了达到工业化应用的程度,人造菱铁矿的造粒研究非常关键。研究了人造菱铁矿造粒的条件及其去除As(Ⅴ)的特征。人造菱铁矿造粒的最佳条件是70℃条件下加热干燥90 min。造粒后的菱铁矿吸附As(Ⅴ)的平衡时间为24 h。准一级和准二级动力学都可以较好地模拟As(Ⅴ)的吸附随时间的变化。在15、25、35和45℃时,与Langmuir吸附等温方程相比,Fre-undlich吸附等温方程可以更好地模拟As(Ⅴ)的吸附等温。pH<3时,As(Ⅴ)的吸附明显降低。共存阴离子HCO3-、SO24-、NO3-或Cl-对材料去除As(Ⅴ)的影响不明显,而SiO23-、PO34-会降低As(Ⅴ)的去除效率。通过XRD和SEM电镜扫描分析,初步得出人造菱铁矿颗粒除As(Ⅴ)可能是化学吸附与共沉淀同时存在的去除过程。
As a trivalent pollutant in drinking water, arsenic causes more and more serious environmental problems. Artificial siderite on the water of arsenic removal efficiency. In order to achieve the degree of industrial applications, artificial siderite granulation research is crucial. The conditions of granulation and the removal of As (Ⅴ) from artificial siderite were studied. The optimum conditions for pelletizing of siderite are heating and drying at 70 ℃ for 90 min. The equilibrium time of as (Ⅴ) adsorption on granulated siderite is 24 h. Quasi-first-order and quasi-second-order kinetics can better simulate the As (Ⅴ) adsorption with time. At 15, 25, 35 and 45 ℃, the Freundlich adsorption isotherm equation can better simulate the adsorption isotherm of As (Ⅴ) than the Langmuir isotherm equation. At pH <3, the adsorption of As (V) was significantly reduced. The effect of coexisting anions HCO3-, SO24-, NO3- or Cl- on the removal of As (Ⅴ) was not obvious, while the removal efficiency of As (Ⅴ) by SiO23- and PO34- decreased. By XRD and SEM scanning analysis, we concluded that the addition of As (Ⅴ) to artificial siderite could be the simultaneous removal of chemical adsorption and coprecipitation.